1. Field of Invention
The invention relates to an apparatus for applying dielectric or metallic materials, silicon dioxide for example, onto a substrate disposed in a vacuum chamber, having a gas inlet leading into the vacuum chamber, having an electron emitter, and having magnets disposed in the area of the vacuum chambers; more particularly, apparatus in which the electron emitter is disposed in a separate generator chamber which is in communication with the vacuum chamber where the generator chamber forms the anode and has an inlet for the process gas.
2. Discussion of Related Art
It is known that, at a certain vaporization rate, quartz vapor decomposes to SiO and O. The coatings obtained by the simple thermal vaporization of quartz usually have an oxygen deficit, so that an oxygen atmosphere is usually maintained during the coating (by the addition of outside oxygen).
An increase of the rate of deposition of stoichiometric SiO.sub.2 coatings can be achieved by activating the SiO.sub.2 vapor by plasma excitation. A variety of reactive vapor deposition methods are known, which operate with an additional plasma excitation, e.g., the ARE (activated reactive deposition) method in which plasma excitation is achieved in electron beam vaporization by means of an additional electrode; furthermore, methods are known which operate by highfrequency plasma excitation.
Furthermore, a plasma generator with an ion beam generator is known (article by D. M. Goebel, G. A. Campbell and R. W. Conn in JOURNAL OF NUCLEAR MATERIAL 121 (1984), 277-282, North Holland Physics Publishing Division, Amsterdam). The generator is disposed in a separate chamber connected to the vacuum chamber, while the approximately cylindrical wall of this separate chamber forms the anode and is provided with an inlet connection for the process gas. The cylindrical chamber is provided with annular solenoids and with tubes for cooling the chamber wall. The electron emitter itself is situated on a portion of the wall closing the one end of the cylindrical chamber facing away from the actual vacuum enclosure.